【摘要】 本研究对三点弯曲试验后的Q235横梁钢试件进行磁记忆信号检测,总结了弹性阶段内构件前后两次在脱离载荷后的法向、切向磁信号分布特征,分析了磁场与弹性应力之间的关系。结果表明:若试件内部存在明显的缺陷或应力集中,切向磁记忆信号H_p(x)有着很强的响应,并且其值会随着载荷的变化呈现一定的正相关性。对于弯曲受载的构件,脱离载荷后构件表面能够"记忆"之前所达到的某种应力状态,并且通过所记忆的磁场信号能够对试件表面存在的缺陷位置做出判断,即沿信号采集方向切向磁场H_p(x)在应力集中位置两侧呈现波峰和波谷状态,法向磁场H_p(y)在应力集中位置两侧磁场发生翻转。更多还原

【Abstract】 The magnetic memory signals of the Q235 steel specimen was collected after a three point bending test. The distribution characteristics of both the normal component H_p(y) and tangential component H_p(x) of the magnetic memory signal on the steel surface in the elastic stage after the load is removed were summarized. The relationship between magnetic field and elastic stress were then analyzed. Experimental results show that the H_p(x) will have a strong response in the presence of obvious defect or stress concentration within specimens. The value of H_p(x) is positively related with the change of the load. After the load is removed, the surface of the sample can memorize a certain stress state achieved before, and the position of defect of the specimen surface can be determined by the memory of the magnetic field signal. Along the direction of signal acquisition, H_p(x) exhibits a state of peaks and troughs at both sides of the stress concentration position. H_p(y) is reversed at both sides of the stress concentration position.更多还原